家蚕细胞周期素家族基因的克隆及结构特征与表达分析

Cloning,Structural Characterization and Expression Analysis of Cyclin Family Genes in Silkworm,Bombyx mori

细胞周期素(cyclin)是推进细胞周期进程最主要的调控因子之一,并与个体发育及肿瘤形成等有关。为研究细胞周期素家族基因在家蚕组织中的表达情况,利用家蚕基因组数据库信息设计引物克隆了家蚕细胞周期素家族的5个基因,对基因序列结构的分析结果表明,cyclinA、cyclinB、cyclinB3基因分别有7个外显子,cyclinE基因有8个外显子,cyclinL1基因只有1个外显子;cyclinA及cyclinE基因存在较多的剪切方式,cyclinA主要包含大小为2 141和2 173 bp的2种转录本,其变化在第7外显子,cyclinE则含有1 422、1 290及1 194 bp等大小不同的序列,变化集中于第5～7外显子,而cyclinB、cyclinB3及cyclinL1基因则相对稳定。克隆的家蚕细胞周期素家族基因的组织表达存在差异:cyclinA基因只在精巢中表达,cyclinB3基因只在精巢和卵巢中有明显的表达,cyclinE基因在丝腺、脑、脂肪体、中肠、马氏管、精巢、卵巢及血液8种组织都有表达,cyclinB和cy-clinL1基因在除丝腺或血液外的其他7种组织检测到表达。研究结果为进一步探究不同细胞周期素在昆虫蜕皮、变态等生理过程中的功能提供了参考。

Cyclin is one of the most important regulatory factors to promote cell cycle progression,and also plays roles in individual development and formation of tumors.In order to explore the tissue expression of cyclin genes in silkworm （Bombyx mori） ,we designed primers according to information from silkworm genome database and cloned 5 cyclin genes.The result of sequence analysis showed that cyclinA,cyclinB and cyclinB3 has 7 exons respectively,cyclinE has 8 exons,and cyclinL1 has only 1 exon.cyclinA and cyclinE have multiple splicing patterns.cyclinA mainly has 2 141 bp and 2 173 bp transcripts with variation at the 7th exon.cyclinE has 1 422 bp,1 290 bp,1194 bp and other length transcripts with variations at the 5th to 7th exons.cyclinB,cyclinB3 and cyclinL1 genes are relatively stable.Tissue expression of the cloned silkworm cyclin family genes was varied.cyclinA gene was only expressed in testis.cyclinB3 gene was expressed apparently in testis and ovarian.cyclinE gene was expressed in all 8 tissues namely silk gland,brain,fat body,midgut,Malpighian tubule,testis,ovarian and hemolymph.cyclinB and cyclinL1 genes were expressed in other 7 tissues except silk gland or hemolymph.The above results provide good references for further study on functions of various cyclins in insect molting,metamorphosis and other physiological processes.